Dynamic Routing : Autonomous System(AS): consists of routers that share info using same protocol. Backbone + areas. Routing within area/domain-Intra Domain Routing, Ext / Inter domain / inter AS Routers connect areas to backbone.
Codes- # sh ip route- C-dir conntd, S-static, I-IGRP, R-RIP, M-mobile, B-BGP, D-EIGRP, EX-EIGRP ext,

O-OSPF, IA-OSPF inter area, E1- OSPF ext type1, E2-OSPF ext type2, E-EGP, I-ISIS, L1-ISIS lvl 1, L2-ISIS lvl 2.

Admn distance: Source’s trustworthiness 0-255 : Directly connected Interface-0, Static route-1, EIGRP sum route-5, Ext BGP-20, Int EIGRP-90, IGRP-100, OSPF-110, ISIS-115, RIP-120, EGP-140, Int BGP-200, Unknown-255.

Interior Routing protos:used within an AS. RIP, IGRP (Dist vect), OSPF (Link state), EIGRP (Bal Hybrid) all layer3.

Distance Vector-RIP-uses 2nd hand info, metric (hops 16 ), slow conv. @ 30 sec, routing loops, counting to infinity.

To Stop Loops: Counting to infinity/exceeding TTL: max.16 loops, Split Horizon: stops info return, Route Poisoning: uses net unreachable entry (metric for down link = infinity), and triggered updates. Hold Downs : stops regular updates from reinstating down link, waits & watches status, work with route poisoning, and use triggered updates.

Link State- OSPF- uses LSP (hello pkts), topology Dbase, SPF algorithm, metric-65533, routing table. needs more power, memory, b/w, fast conv @ 2-12 hrs(uses DR designated Router), LSP time stamps,

Balanced Hybrid-IS-IS, EIGRP: combines and uses best of both above. Link state triggers. Classfull routing: summarizing routing info by major network nos.(RIP, IGRP), Classless and Prefix routing : allows contiguous blocks of hosts, subnets or nets to be represented by a single route. Cost= Path Cost: based on hope, bw, etc. to determine the best route. Lower the cost value better the path. Routing metric: method by which routing algorithm decides one route is better than other. Stored in routing table. Includes bw, comm cost, delay, hop count, load, MTU, path cost, and reliability.

RIP: dynamic, dist vect, classful routing proto, no support prefix routing. Provides IP dest add, metric-hop count (16), IP add of next router in the way, marker & flags (recent route change), timer, Hold downs, Split horizon, Poison rev, slow conv, loops. Timers: update-30sec, invalid-180sec, flush-240sec., hold-180sec, Admn Dist.: 120,
RIP pkt format: command1,ver no1, zero2, add family ID2, zero2, add4, zero4, zero4, metric4.

Enab RIP: cancel all stat/def routes, config t, Enab RIP(# router rip),Enab net (# net work x.x.0.0), R# wr mem

Testing RIP: # sh ip route rip, # ping [add]. Passive RIP: stops router from advt to internet. Commands: config t,

# router rip, # network 172.16.0.0, # passive serial 1 ( serial 1 connects the local net to the internet),

Neighbor RIP: WAN link (frame relay) doesn’t broadcast RIP update by default. use neighbor command to solve this.

config t, # router rip, # network 172.16.0.0, # neighbor 172.18.3.10. RIP Broadcast : sending update to 255.255.255.255 via e0

Monitoring RIP: R # sh ip route rip-sh only RIP routes, # sh ip protocol-sh RIP timers, net ID, routing info sources,

# sh ip interface: shows interface config and statistics, R# debug ip rip: turns on RIP debugging-shows RIP updates live,

# undebug ip rip: stops debug, R # trace 172.16.50.2: sh path to dest add, config t # no router rip: stops running RIP proto.

IGRP: Dist vect, cisco prop, scalability, fast convergence, multi paths (def 4, max 6) & unequal load balancing, Periodic & Flash updates, no VLSM, complex metric (1-255) [delay-media speed (10mb=100=1ms), bw (1.2kb-10Gb), reliability (1-255optm), load (optm 0-255), MTU], hold down, poison rev, split horizon,

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